In Circuit Test Program Release: 6 Checks Before Handover An in circuit test program is released once and then trusted for years, which is why the release review matters more than any single test run. A program that passes on the developer’s desk can still miss a net, hold a…

Soak Time in Reflow: A Complete Setting Guide Soak time is the period in a reflow profile during which the board is held below the melting point of the alloy, usually between about 150 °C and 190 °C. Its purpose is to bring the whole assembly to a uniform temperature…

Nozzle Clogging: 5 Causes and How to Prevent Them Nozzle clogging is the partial or complete blockage of the dispensing orifice, and on a jetting or dispensing machine it produces a missing or undersized deposit rather than a machine fault. The valve keeps firing, the program keeps running, and the…

Solder Paste Warm Up: 5 Steps to Control Open Time on the Line Solder paste warm up is a controlled step rather than a waiting period. A sealed jar that comes out of cold storage has to reach room temperature before the lid is opened, because condensation on cold paste…

AOI Inspection Calibration: 6 Checks for Cameras and Lighting An AOI inspection machine decides pass or fail from an image, so everything that shapes that image has to be under control. Camera focus, pixel scale, light intensity and colour settings all change with age, and each one moves the decision…

Flying Probe Test Maintenance: 5 Checks for Probe Wear and Accuracy Flying probe test has no fixture to go out of alignment, so the moving parts and the probe tips carry the whole measurement. That is why a flying probe machine drifts slowly instead of failing suddenly: contact resistance rises,…

Paste Drying on the Stencil: 7 Warning Signs Paste drying on the stencil is the gradual loss of solvent from the working bead, and it is one of the most common causes of a mid-shift change in print quality. The paste stiffens, the bead stops rolling, and the deposits become…

Fillet Height: How to Measure and Specify It Fillet height is the distance the solder rises up the side of a component termination, measured from the surface of the pad to the top of the solder at the point where it meets the part. It is the dimension that visual…

Panel Tab Routing: 6 Rules for Clean Depaneling Panel tab routing is the practice of leaving small bridges of laminate between a board and its panel frame, separating them later with a router. The tabs hold the board through printing, placement, reflow and test, and they are cut at the…

Void Formation in Solder Joints: 6 Causes and Fixes Void formation is the trapping of gas inside a solder joint as the alloy solidifies, leaving pockets that reduce the load-bearing area. It is normal to find some voids in any reflowed joint, and the question is not whether they exist…